1. Field of the Invention
The present invention relates to a position detection device, an apparatus using the same, an exposure apparatus, and a device manufacturing method using the same and, more particularly, to a technique suitably used when the position information of an object is detected on the nanometer order, and the surface of the object is optically processed using the position information, or a microstructure on the object surface is inspected.
Also, the present invention relates to a technique suitable for an apparatus for detecting the position information of an object such as a mask, wafer, or the like with high precision by observing images of alignment marks formed on the object, aligning the object on the basis of the detected position information, and manufacturing a device or the like in a projection exposure apparatus which is used in the manufacture of various kinds of devices such as semiconductor ICs, LSIs, CCDs, liquid crystal panels, magnetic heads, and the like using the step-and-repeat or step-and-scan method.
2. Related Background Art
In recent exposure apparatuses for manufacturing devices, higher-precision alignment systems are required for aligning a wafer and reticle relative to each other in the exposure apparatus as the resolution of the pattern image to be projected becomes higher. Especially, the exposure apparatus must obtain both a high-resolution pattern to be projected and high-precision position information.
Conventionally, in an optical working tool (micro-working tool) for manufacturing a device by sequentially forming electronic circuit patterns on an object surface (silicon surface), an inspection tool for inspecting a microstructure such as a molecular structure or the like on the object surface, and the like, a position detection device for detecting the position information of the object is used, and driving of the object is controlled using the obtained position information.
In position detection devices used in the manufacture of devices disclosed in, e.g., Japanese Laid-Open Patent Nos. 4-267536, 4-186716, 8-321454, and the like, alignment marks formed on the object surface are irradiated with alignment light, optical images of the alignment marks are detected using an observation system (TV camera, and the like), and the detected images are subjected to image processing to detect the position information of the object.
Also, in a position detection device disclosed in Japanese Laid-Open Patent No. 7-270123, a diffraction grating is disposed on the object surface, and the position information of the object is detected using ±n-th-order diffracted light produced by the diffraction grating.
In the position detection device that obtains the position information of the object by optically detecting the positions of the alignment marks formed on the object surface, the detection precision is limited by a spread of optical images arising from the wavelength of alignment light, manufacturing errors of an alignment detection system, aberrations of the alignment optical system, and the like, and it is very hard to obtain precision on the subnanometer order.
Also, even in exposure on the nanometer order, since the detection precision of the alignment optical system has the above-mentioned limitations, it is very hard to obtain precision on the subnanometer order.